Do you ever use standby on your transponder?

From the 2005 AIM...

4-1-19. TRANSPONDER OPERATION

a. General:

3. Civil and military transponders should be adjusted to the "on" or normal
operating position as late as practicable prior to takeoff and to "off" or
"standby" as soon as practicable after completing landing roll, unless the
change to "standby" has been accomplished previously at the request of ATC.

d. Transponder IDENT Featu

1. The transponder shall be operated only as specified by ATC. Activate the
"IDENT" feature only upon request of the ATC controller.



"Newps" wrote in message
...


Judah wrote:

Newps wrote in
:


You heard wrong.


Funny, this aviation business.

It seems that about 50% of the stuff you hear from people who are
supposed
to know more than you - instructors, experienced pilots, etc., etc. - is
urban legend, stated as if it were plain fact.



It used to be right, but times and technology change and those reasons
are no longer valid.

"Standby" used to be a common function on vacuum tube equipment, keeping the
filaments hot, but cutting the plate current, so the device could be turned
"ON" and operate instantly, without having to wait for the filaments to heat
up and start emmitting. Some solid state equipment retained this function,
just because people were used to it, and operators had been taught to use it.


Is it possible that this is the case with the transponder? Anyone know of a
tube transponder?

I always learned that you are to use only two modes on the transponder -
"Standby" and "ALT" (or mode "C"). ON and OFF were never to be selected.

I was also instructed to IDENT after acknowledging a transponder code change,
even if not specifically requested to do so by ATC. The reasoning was that
they will see your ident immediately, while it may take them up to a minute
to see your code change.

G Faris

"Greg Farris" wrote"
"Standby" used to be a common function on vacuum tube
equipment, keeping the filaments hot, but cutting the plate
current, so the device could be turned "ON" and operate
instantly, without having to wait for the filaments to heat up
and start emmitting. Some solid state equipment retained
this function, just because people were used to it, and
operators had been taught to use it.
...

They all must have that function, as it's in the TSO! I'm sure it
was at the behest of ATC back when written, not for circuit design
considerations. Latter ain't FAA's problem, but the
manufacturers'.


Is it possible that this is the case with the transponder? Anyone
know of a tube transponder?

ebay.com now and then. Shipping will far exceed winning bid
price.

Fred F.

Greg,

I was also instructed to IDENT after acknowledging a transponder code change,
even if not specifically requested to do so by ATC.


Alas, and it would have been so easy for your instructor (and all the others out
there) to read the AIM.

--
Thomas Borchert (EDDH)

Judah,

It seems that about 50% of the stuff you hear from people who are supposed
to know more than you - instructors, experienced pilots, etc., etc. - is
urban legend, stated as if it were plain fact.


Hey, and this is the easy stuff - transponder operation is covered in the
AIM, which, for all practical purpose, has quasi-regulatory character (I
know, another discussion just waiting to happen).

Then, there's the less obvious (to some) stuff, like downwind turns, running
lean-of-peak or aging of composites.

--
Thomas Borchert (EDDH)

"Greg Farris" wrote in message
...

I was also instructed to IDENT after acknowledging a transponder code
change,
even if not specifically requested to do so by ATC. The reasoning was that
they will see your ident immediately, while it may take them up to a
minute
to see your code change.


Did your instructor say why that was the case? Did he believe the radar
antenna rotated faster when the IDENT button was activated?

Greg Farris wrote:

Is it possible that this is the case with the transponder? Anyone know of a
tube transponder?

Yeah, KT76 and lots of others. Microwave tubes are still in use.
Actually the biggest thing you want to use STANDBY for is many encoders
need preheat on their pressure sensing element.

I always learned that you are to use only two modes on the transponder -
"Standby" and "ALT" (or mode "C"). ON and OFF were never to be selected.

Fine if you have a avionics master, but I'd tell you to shut your
transponder off while cranking the engine. Further ON (or Mode A)
is required when ATC asks you to stop altitude squawk (has happened
to me).


I was also instructed to IDENT after acknowledging a transponder code change,
even if not specifically requested to do so by ATC. The reasoning was that
they will see your ident immediately, while it may take them up to a minute
to see your code change.

Not only is this the wrong procedure, it's bull****. The IDENT and the
code
are transmitted with the same frequency.

cjcampbell wrote:

Some transponders have a 'ground' mode. The Garmin G-1000 turns its
transponder on and off automatically.


The Garmin transponders automatically turn on and off (my GTX33 does)
based I suppose on noticing that the encoded altitude has jumped since
it was turned on.

The the SL70 (formerly Apollo) transponder also has an engage mode if
an attached device (like your GPS) says it is now moving at a certain
threshold speed.